Former Prime Minister Hassan Diab returned to Beirut on Wednesday evening, amid a political campaign led by Hizbullah and Amal against Lead investigator in Beirut port blast, judge Tarek Bitar.

Bitar in August subpoenaed Diab for interrogation on September 20 after he failed to show up for questioning.

Heavy fighting claimed at least six lives and left dozens wounded in and around the Tayyouneh area on Thursday as an escalation of tensions around last year's massive portside explosion turned parts of Beirut's southern edge into a war-zone.

The army deployed tanks and troops to quell street battles that sparked memories of the 1975-1990 civil war for a city already traumatized by last year's blast disaster and Lebanon's worst-ever economic crisis.

Lebanese Forces party chief Samir Geagea asked Wednesday the government, President Michel Aoun and Prime Minister Najib Miqati not to "bow to Hizbullah's intimidation" concerning the dismissal of lead investigator into the port blast case, Judge Tarek Bitar.

“If they stop the investigations, they must resign immediately,” he said.

A Cabinet session scheduled for Wednesday was postponed following consultations and an agreement between President Michel Aoun and Prime Minister Najib Miqati, the Presidency said, as efforts continued to resolve a political standoff over the work of Beirut port blast investigator Judge Tarek Bitar.

Justice Minister Henri Khoury is supposed to present “balanced” suggestions to Cabinet on Wednesday on the controversy surrounding Beirut port blast investigator Judge Tarek Bitar, media reports said, after an escalation by Hizbullah and its allies forced the suspension of Tuesday’s Cabinet session.

Ex-minister and incumbent MP Ali Hassan Khalil considered the arrest warrant issued against him by the judicial investigator Tarek Bitar “illegal.”

“It is not based on any legal justification,” he said Tuesday, in a televised interview.

A Cessna-172 training plane belonging to the Aeroclub of Lebanon crashed into the sea off the Lebanese town of Halat on Wednesday with two people on board.

Member of the Democratic Gathering, MP Wael Abu Faour said Wednesday in a statement that “the Higher Defense Council refused to grant permission to prosecute Director of State Security Major General (Tony) Saliba, because the latter might expose all the correspondences with the presidential palace.”

“As expected,” he said, adding that “the reason why the permission to prosecute Saliba wasn’t granted is clear.”

The lead spokesperson for the external affairs of the EU, Peter Stano, said Tuesday that the Beirut port blast investigation has to be “completed as soon as possible,” and that it should be impartial, credible and transparent.

“The European Union recalls that the investigation into the Beirut Port blast should be completed as soon as possible, and that it should be impartial, credible, transparent as well as independent,” Stano said in a video message.

A Cabinet session was suspended Tuesday and adjourned to Wednesday, after it witnessed a heated debate over a demand by the ministers of Hizbullah, Amal Movement and Marada Movement for a stance on Beirut port blast investigator Judge Tarek Bitar, TV networks said.